March 2017 I: The outdoor tomato growing Season

Growing tomatoes outdoors in the UK requires a certain level of commitment.

For a start, the first 2 months of the ‘season’ are not outdoors, they need to take place indoors, or in a protected outdoor space such as a lean-to. Without the warmth and protection from wind, young tomato plants will not grow. With that protection, their growth rate is fairly astonishing.

The tomato season can be split into four phases:

  1. Germination of seeds.
  2. Vegetative growth prior the first flower emerging.
  3. Flowering and fruit set.
  4. Fruit growth and ripening.

By studying my tomato plants the past 5 years, I can say with confidence that most tomato strains, if sown in early March and grown indoors until late April/early May, will usually yield their first ripe tomato within 18 – 20 weeks.

One blog post is nowhere near enough to teach you how to grow tomatoes and there is a well-established blog where I learned much of my skill in growing tomatoes ( ), produced by Mr Nick Chenhall, until recently based in the West Midlands but now relocated to Devon. If you want a weekly newsletter through the season giving tips on tomato growing, Nick’s website is your port of call.

My top tips are these:

  1. Germinate tomato seeds with plenty of heat: I place my seed trays on top of our outside gas boiler for 4 – 5 days and germination is uniformly excellent. Leaving them indoors at room temperature is less secure.
  2. Save your own seeds from plants which grew well in pots, outdoors, in your home area. You have selected seeds suited to your climate, not seeds created in China or wherever.
  3. Once you have found some favourites which work well, stick with them as bankers. My list of bankers includes Maskotka, Alicante, Super Marmande, Sungold and Tigerella.
  4. Spend one season documenting a few things about tomato plants each week – you will quickly learn that there is a pretty set timetable for tomato plant evolution from seed to ripe fruit. Things to look at are numbers of leaves and stems on young plants, number of trusses, flowers and fruit set on maturing plants and number of fruit harvested from mature plants.
  5. Be prepared to experiment: people who say that tomato plant pots should not be stood in water in high summer as it damages roots clearly have not done this in NW London – it generates fantastic crops! Tomatoes will absorb a gallon of water a day from beneath during warm sunny days of July and early August. Plants drying out is a far greater problem.

Here is a timetable which should work well for 2017:

  1. Sow seeds March 10th
  2. Pick seedlings to 8cm pots 20/21st March.
  3. Pot on to 15cm pots 16th April.
  4. Pot into final pots, 30cm diameter on 14 th May.

On that timetable, you may need to put plants in a shed, garage or the like if there are cold nights in the second half of May. However, tomato plants are hardy once established and will happily survive the odd night at 5C.

Author: Rhys

Rhys trained as a research biologist, working for a decade in the cancer research charity sector, before completing an MBA and working in management consultancy, technology transfer and early technology investment spaces, mostly working with UK academics to turn their scientific discoveries into value for society. AS a younger man, he was fascinated with mountains, both climbing them and ski-ing down them. Whilst living in Scotland, he completed a round of (then) all 277 Munros, the independent mountains over 3000ft originally complied as a list by Munro. He also spent his holidays representing the Ski Club of GB, as a Representative and Party Leader between 1990 and 1997. During that time, he found to his bemusement that he was able to predict, without understanding fully why, to a remarkable degree of accuracy, when good snow conditions would occur in the Alps, gaining an unworthy reputation for predictive genius in 1990 when predicting the evolution of the 1989/90 winter in Wengen, Switzerland for his CEO boss. He used this skill for the next seven years to ensure that he enjoyed powder snow pretty much every time he went ski-ing. An MD student he was training in Oxford also impressed his wife by taking Rhys' advice about when to take her to Italy in the mid 1990s! In recent years, Rhys has turned his mind toward how to grow prize tomatoes, winning several prizes in local and London shows and has, in the past 3 years, moved toward taking over a 50 square metre urban vegetable patch, which he has turned into a no-dig area since autumn 2014.

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